Tuesday, December 20, 2011

Generally Mild, Few Drops Of Rain Around Today

We're starting today on a mild note around the region as a slow-moving frontal boundary lies across the Delaware Valley.  Temperatures are generally in the 40's, with 50 in Philadelphia as we head out the door.  There won't be much movement in temperature today in the city and points north as we reside on the "cooler" side of the front (there isn't much in the way of cold lurking just north of the boundary and one has to travel to the Poconos to get into sufficiently chilled air) and skies will remain mainly cloudy through the day.  A few breaks in the clouds can't be ruled out but on the whole, skies should be rather gray and dull.   A few sprinkles or showers can't be ruled out in spots near the frontal boundary today as well but most of the region should be dry.   Temperatures hold steady in the 40's north of the city, perhaps nudging above 50 south of town for a while today while the city hangs out a couple of degrees on either side of 50.

The frontal boundary stalls to our south, returning tonight as a warm front as a storm system in the Plains pushes on east.  Showers will spread into the region later this evening, pushing northeast.  While precipitation for many should be liquid, the Poconos run the risk of seeing some freezing rain at the onset before temperatures at the surface warm above freezing.   Occasional showers will be with us through tomorrow as the storm system pushes into the Great Lakes and passes well to our north, with areas of showers moving through as temperatures nudge towards 60 degrees in the city tomorrow afternoon.

Regarding the "threat" of a White Christmas, there's still a good deal of uncertainty in modeling on the 24th/25th event in terms of timing but odds favor rain in the city and south/east at this point regardless of timing.  There's simply a lack of cold enough air and the low is a bit too weak to pull down additional cold air to get snow into the city.  There could be a mix of rain/snow north/west of the city but as the storm moves through that mix could transition to rain.  The best chances of snow at this point would lie in the Poconos and Northwest Jersey.  Still plenty of time to monitor things with the Christmas low but snow doesn't seem too likely around the city as of this morning.